254 THE SYSTEM OF F-\EM-YARD MANURING . 



amoimt of produce reaped in the Eliine district of Hesse 



former average. 



The productiveness of the icheat land in the Bhine dis- 

 trict of Hesse has therefore declined somewhat more than 

 one-fifth. 



I know all that may be urged against the accuracy of 

 these figures severally, and theii' trustworthiness collec- 

 tively ; but if they -contain eiTors, the impartial observer 

 must see that these must tend to the plus as well as to 

 the minus side, and that it would be most extraordinary 

 in the presence of />/?/.5 errors that all the estimates 

 should have fallen out on the minus side. 



There is, however, a very simple, and at the same time 

 infallible and iiTefutable, proof of the correctness of the 

 conclusions di'awn from these figiu'es, in the fact that the 

 cultivation of wheat is on the decrease, that of lye on 

 the increase, in Ehine Hesse, and that many fields on 

 which wheat was formerly grown are now tm-ned into 

 rye fields. 



Properly understood, the change fi'om wheat to rye 

 always argues a deterioration in the quahty of the soil ; 

 the farmer begins to gi'ow lye in a wheat field only when 

 the latter no longer gives remunerative wheat crops. 



In Ehine Hesse, a 4 J fold produce of rye is considered 

 an average crop ; a wheat soil, therefore, capable of 

 giving only four-fifths of an average wheat-crop, can pro- 

 duce a full average rye-crop. 



Kow the average produce of rye in the fifteen years is 



